pull only rows where field 2 is 'WI' in tab-delimited file

[polka4ever]

hello! I have a story problem for you. I have a tab-delimited file. The 2nd field is the "state" field, and I want to pull out of this file, and write to a NEW file, only the rows that have Wisconsin as their state. 'WI' I believe I need to use "split" but not sure how. This is how far I've gotten. I'm horrible at Perl.

#!/usr/bin/perl
open (FILE, "<lotsofstates.data");
while (<FILE>) {

 

[polka4ever]

I bet it is very similar to what was posted for kre1973 ... except that I need the "WI" or "OR" or "NE" or whatever state I need to occur in field 2 - instead of, say, the last name field or something.

 

[RottPaws]

You could do it a couple of different ways, but I'd probably go with the split as you suggested and check the value of the second element.

#Assign the filename to a variable
my $filename = 'lotsofstates.data';
my @fields;

#Assign the state to look for
my $state_to_find='WI';

#Open the file or print an error message on failure
open FILE, "< $filename" or die "$filename : $!\n";

#Assign the lines of the file to an array
my @lines = <FILE>; 

close FILE;

#Loop through the lines
foreach $this_line (@lines){
    
    #Split the line on commas
    @fields = split (',', $this_line);
    
    #Check the value of the 2nd field (array elements start at 0)
    if ($fields[1] eq $state_to_find){
        #code that does stuff;
    }
}

Note: This is assuming the data does not contain any newline/CRLF chracters or commas in the data. Those cases will require special handling.

_________
Rott Paws

...It's not a bug. It's an undocumented feature!!!

 

[spookie]

Since you have a tab limited file, change line

@fields = split (',', $this_line);

to

@fields = split ('\t', $this_line);

given by RottPaws

--------------------------------------------------------------------------
I never set a goal because u never know whats going to happen tommorow.

 

[stevexff]

Alternative crude solution. has the benefit of allowing you to specify the state to select on the command line, and search a whole list of files if you need to. Just pipe the output to a file of your choice...

use strict;
use warnings;
my $state = uc(shift);

while (<>) {
    print if (/\t$state\t/);
}

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[RottPaws]

Good catch, spookie. I deal with comma delimited files so much I missed that....

But you'll need to use double-quotes instead of single quotes. As in:

@fields = split ("\t", $this_line);

_________
Rott Paws

...It's not a bug. It's an undocumented feature!!!

 

[spookie]

RottPaws
It works with ' as well.


--------------------------------------------------------------------------
I never set a goal because u never know whats going to happen tommorow.

 

[KevinADC]

But you'll need to use double-quotes instead of single quotes. As in:

Not in the split function. The first argument of split() is a regexp pattern, so the single-quotes are just replacing the forward slash as the delimiters of the regexp. Now if it were the join() function, double-quotes would be necessary as the first argument to join is a string, not a regexp pattern.

 

[RottPaws]

I didn't know that. Thanks.

_________
Rott Paws

...It's not a bug. It's an undocumented feature!!!